A cap for a food package

ABSTRACT

Disclosed herein is a cap configured to interact with a neck. In some embodiments, the cap comprises an inner wall portion and at least one cutting element projecting radially inwards from the inner wall portion. In some embodiments, the cutting element has a hinge portion connected to the inner wall portion, and a cutting portion extending radially inwards from the hinge portion, wherein a first axial thickness of the hinge portion is between 35 and 80% of a second axial thickness of the cutting portion. Also disclosed herein is an assembly comprising the cap and a spout having a membrane closing a tubular member of the spout.

TECHNICAL FIELD

The present solution relates to a cap for a food package. In particular,the present solution relates to a cap being capable of cutting off amembrane sealing an end of an associated spout.

BACKGROUND

Food packages are generally provided with an opening device in order tofacilitate discharging of the enclosed food product. The opening devicemay either be an irreversible opening, i.e. once the package is openedit may not be closed again, or a reclosable opening device. In order toextend the shelf-life and quality of the food product the latter isoften desired. A common way of providing a reclosable opening device isto arrange a threaded neck including a pouring spout on the upper partof the package. The threaded neck is designed such that it may receive acap, including internal threads, such that the cap is capable of beingunscrewed from the neck. Since the cap covers the open spout of theneck, the enclosed food product is protected from the outer environmentand the quality of the product may thus be preserved during some time.

Although the above solution provides an improvement over theirreversible openings which always remain open, it is still possible forpolluted media to enter the interior of the package via the neck/capinterface, e.g. via the threads. Hence, further improvements have beenproposed for sealing the open spout of the neck when the package isstored.

In WO2011144569 a solution is described in which the spout is providedwith a membrane. The membrane, which initially is connected to the spoutleaving the spout perfectly closed, is cut from the spout during anopening action, i.e. when the cap is unscrewed from the neck.

For improving the cutting action, WO2014202518 describes a cap havingcutting elements projecting radially inwards. Each cutting element has afree end portion, wherein the free end portion is provided with a blunttip and a comparatively sharper cutting edge on a lateral side of thefree end portion.

Although the above-mentioned solutions provide well-proven and reliableopening and re-sealing of packages, it has been realized that furtherimprovements are desirable especially in terms of the cutting action,i.e. when the membrane is initially cut loose from the spout. If themembrane is not cut properly re-sealing will be affected negatively.

Thus, there is a need for a cap having cutting elements providingimproved cutting action of the membrane which allows for enhancedre-sealing in order to preserve the quality of a food product enclosedwithin a food package, as well as pro-longing the shelf life of the foodproduct.

SUMMARY

It is, therefore, an object of the present invention to overcome oralleviate the above described problems.

According to a first aspect, the present solution is a cap arranged tointeract with a neck, where the cap comprises an inner wall portionprovided with at least one cutting element projecting radially inwards.The cutting element has a hinge portion connected to the inner wallportion and a cutting portion which extends radially inwards from thehinge portion, wherein the axial thickness of the hinge portion isbetween 35 and 80% of the axial thickness of the cutting portion.

Now, the relation between the axial thickness K2 of the hinge portionand the axial thickness K1 of the cutting portion may be, such that3/7K1≤K2≤ 5/7K1.

Expressed in absolute numbers, the axial thickness of the hinge portionmay be between 0.3 and 0.5 mm.

Also, the number of cutting elements may be between 1 and 7. Theirfunction is to cut off a membrane from a pouring spout on a packagingcontainer. The cutting action will be readily performed with only onecutting element, but at least three are necessary to retain the membraneafter cutting it off from the spout.

According to another aspect, the present solution is an assembly whichcomprises a cap mentioned in the beginning of this section and which hasa spout with a membrane closing a tubular member of the spout.

In embodiment of the present solution, the tubular member may comprisesa main body and an end portion releasably attached to said membrane,wherein the axial thickness (K1) of the cutting portion of the cuttingelement is between 200 and 400% of the axial length (L1) of the endportion.

In another embodiment of the present solution the membrane comprises amembrane flange with an outer portion extending radially outside the endportion of the tubular member.

It should be mentioned here that in one variant the axial length (L1) ofthe end portion is between 15-65% of the axial thickness (D1) of theouter portion of the membrane flange. In another variant the axiallength of the end portion may be between 20-50% of the axial thickness(D1) of the outer portion of the membrane flange.

In yet another embodiment of the assembly according to the presentsolution the membrane flange further comprises an inner portion, wheresaid end portion of the tubular member is attached to the interfacebetween the inner and outer portions of the membrane flange, wherein theaxial thickness (D2) of the inner portion is equal to, or less than theaxial thickness (D1) of the outer portion.

In yet another embodiment of the assembly according to the presentsolution the inner surface of the inner portion of the membrane flangeis arranged at an axial distance (H1) from the inner surface of theouter portion of the membrane flange.

In another embodiment of the solution it is proposed to make the innersurface of the inner portion of the membrane flange and the innersurface of the outer portion of the membrane flange parallel in relationto each other.

In yet another embodiment of the solution it is proposed to make theouter surface of the inner portion of the membrane flange and the outersurface of the outer portion of the membrane flange coincide with eachother.

Finally, in yet another embodiment of the present solution it isproposed to have the membrane comprise a sealing lip protruding into thetubular member, wherein the sealing lip extends from an axial positionbeing arranged at a distance (H1) from the axial end position of the endportion of the tubular member (110). Here the outer radius of thecutting portion of the at least one cutting element may corresponds tothe outer radius of the sealing lip.

BRIEF DESCRIPTION OF THE DRAWINGS

The above, as well as additional objects, features, and advantages ofthe present solution, will be better understood through the followingillustrative and non-limiting detailed description of preferredembodiments of the present invention, with reference to the appendeddrawings, wherein:

FIG. 1 is a schematic view of a package having a spout according to anembodiment;

FIG. 2a is a cross-sectional view of a cap for use with a spoutaccording to various embodiments;

FIG. 2b is a cross-sectional view of a neck, including a spout accordingto an embodiment;

FIG. 2c is a top view of a cutting element for separating a membranefrom a neck according to an embodiment;

FIGS. 2d-f are side views of a cutting element according to variousembodiments;

FIGS. 3-6 are cross-sectional views of an assembly comprising a neck andcap during closing of the spout;

FIG. 7a is a cross-sectional view of a spout according to an embodiment;and

FIG. 7b is an enlarged view of parts of the spout shown in FIG. 7 a.

DETAILED DESCRIPTION

With reference to FIG. 1 an example of a food package 10 isschematically shown. The food package 10 has a shape of a bottle formedby a body portion 11, which may preferably be made of a carton-basedlaminate and a top portion 12, which may preferably be made of plastic.The top portion 12 is provided with a neck 20 forming the upper part ofthe plastic top portion 12. The neck 20 may be integrally formed withthe top portion 12, such that the entire top portion 12, including theneck 20, may be manufactured as a single piece.

A cap 30 is arranged onto the neck for sealing a spout 100 (see e.g.FIG. 2b ) forming the upper end of the neck 20. The cap 30 mayoptionally be provided with a tamper ring 40 as is well known in theart.

The package 10 may be manufactured by first forming a sleeve of thecarton-based laminate, i.e. a tubular body extending between two openends. In a second step, performed before, after, or in parallel with thesleeve forming, the plastic top portion 12 is manufactured by molding.The plastic top portion 12 may, as is shown in FIG. 1, comprise ashoulder section 13 arranged below the neck 20 and to which the tubularbody is later attached. The shoulder section 13 is thus arranged toconnect the sleeve, which forms basis for the body portion 11, to theneck 20. The neck 20 is preferably provided with threads for engagingwith corresponding threads of the cap 30 including the tamper ring 40.As previously explained, the neck 20 and the shoulder section 13 may beprovided as one piece, or as two separate pieces which are moldedtogether.

After the cap 30 is screwed onto the top portion 12 the sleeve is filledwith food content. Preferably, this is done by turning the sleeve andthe top portion 12 assembly upside down, such that the remaining openend of the sleeve is facing upwards. After being filled the open end ofthe sleeve may be sealed and folded to a flat bottom as illustrated inFIG. 1.

Alternatively, the cap 30 is screwed onto the top portion 12 after thepackage 10 is filled. This may e.g. be the case if the neck 20 isprovided with a membrane 150 (see FIG. 2b and onward) sealing the spout100 of the neck 20, which will be described in more detail below.

Now turning to FIGS. 2a and 2b details of the neck 20 and cap 30 will bedescribed further. The cap 30, including the tamper ring 40, is shown inFIG. 2a . The cap 30 has a lower portion 31 being provided with internalthreads 32. The threads 32 are configured to engage with correspondingthreads 22 of the neck 20 (see e.g. FIG. 2b ). The lower portion 31extends into an upper portion 33 which forms the closed upper end of thecap 30. The interior of the upper portion 33 is provided with means forseparating the membrane 150 from the spout 100, as well as for retainingthe cut-off membrane 150.

For this purpose, following the threads 32 cutting elements 50 arearranged. The purpose of the cutting elements or knives 50 is topenetrate a section of the spout 100, immediately below the membrane150, and to separate that membrane 150 from the rest of the spout 100.After that step, the cutting elements 50 serve the purpose of securingthe membrane 150 in an axial position (i.e along the A-axis in FIG. 2A)between the cutting elements 50 and the interior of the top part of theupper portion 33. This will reduce the amount of litter generated, yetthe technical reason is that the membrane 150 serves an importantpurpose when resealing the closure. There are a number of cuttingelements 50 distributed around the perimeter of the upper portion 33. Inthe present embodiment there are five. The number of cutting elements 50will depend on several factors, yet one important factor is the risingof the threads 32. The cutting action is effected when unscrewing thecap 30, and the cutting elements 50 will follow the rotational motion ofthe cap 30 as well as the axial movement thereof, all relative to theneck 20. This implies that the cutting action, or “removal action” to bemore general, has to be finalized within a certain turning angle sinceotherwise the axial movement will move the cutting element 50 out ofreach from the area to be cut. So, the steeper the rising of thethreads, the more cutting elements 50 are needed. On the other hand,each cutting element 50 will generate a torque resistance when the cap30 is unscrewed the first time, and in order to reduce the openingtorque to an acceptable level the cap 30 should not have too manycutting elements 50. Hence, for the present embodiment five cuttingelements 50 have been used, yet it is up to the skilled person to deducea suitable number. In general, one cutting element 50 is sufficient toperform the cutting action in order to separate the membrane 150 fromthe spout 100. However, it has been found that at least three cuttingelements 50 are necessary to perform the cutting and the membrane 150retaining action, after the membrane 150 has been cut off from the spout100.

At about the same axial position as the cutting elements 50 stopelements 60 are arranged. In the present embodiment the stop elements 60are realized by stop ledges, i.e. flanges extending from the top part ofthe upper portion 33 down to a specific axial position, and a smalldistance radially inwards. It should be noted that within the context ofthis specification, all references to “axial” or “radial” should beinterpreted as shown by the dashed arrows in FIG. 2a . The axialdirection is indicated by the letter “A”, while the radial direction isindicated by the letter “R”.

In the present embodiment there are a total of five stop ledges 60 andthey are dimensioned so as to allow for the membrane 150 to fit betweenthem. The purpose of the stop elements 60 is to prevent the cap 30 frombeing screwed too far down (i.e. in a closing direction) onto the neck20, and thus to prevent damage to the membrane 150 during application ofthe cap 30 or when resealing the closure after initial opening. The stopelements 60 of the cap 30 cooperate with a counter element 24 of theneck 20 (see FIG. 2b ). In this embodiment the counter element 24 isrepresented as a shoulder extending radially outwards.

There are other means for preventing the cap 30 from rotating anyfurther once it has reached a certain position on the neck 20. Examplesinclude various stop arrangement in the thread 32, may it be a physicalblock at the end of the threads 22 of the neck 20 which the threads 32cannot override, or a change in rising of the threads 22 of the neck 20preventing further rotation of the cap 30. There are more optionsavailable. The solution used in the present embodiment is simple,straightforward, does not involve any other operational parts of the cap30 or neck 20, as well as being predictable, straightforward andproviding a distinct stop.

An example of a cutting element 50 is shown in further details in FIG.2c . In this drawing the cutting element 50 is shown from above. As isclearly shown the cutting element 50 is attached to the inner perimeterof the cap 30, at an axial position indicated in FIG. 2a . The cuttingelement 50 is allowed to pivot by means of a hinge connection with theinner perimeter of the cap 30 as will be further described withreference to FIGS. 2d-f . As will be explained, the hinge connection isin this embodiment realized by a reduced thickness at an area 52immediately adjacent to the inner perimeter of the cap 30.

The region 54 is the cutting region of the cutting element 50, and inthis region the thickness of the cutting element 50 is reduced to form acutting edge 54. The cutting edge 54 may be rectilinear, as in thepresent embodiment.

The free end 56, remote to the hinged attachment may preferably beblunt, and may preferably be less sharp than the cutting region 54. Theresult is the benefit that the free end 56 is not prone to damage theconnection region between the membrane 150 and the rest of the spout 100when it is not supposed to. This may e.g. be important when the cap 30is arranged on the spout 100 for the first time.

FIGS. 2d-f show various embodiments of the cutting element 50, takenalong the line I-I in FIG. 2c . The inner wall of the cap 30, heredenoted by reference numeral 33, is provided with the cutting element50. The cutting element 50 has a hinge portion 52 connected to the innerwall 33, and a cutting portion 53 extending radially inwards, i.e.towards the centre of the cap 30, from the hinge portion 52. The axialthickness K2 of the hinge portion 52 is preferably between 35 and 80% ofthe axial thickness K1 of the cutting portion 53. Even more preferably,the axial thickness of K2 of the hinge portion 52 is between 3/7 and 5/7of the axial thickness K1 of the cutting portion 53. In one specificexample, the axial thickness K2 of the hinge portion 52 is 0.4 mm, whilethe axial thickness K1 of the cutting portion 53 is 0.68 mm.

The inventors have surprisingly realized that by selecting the axialthickness K2 of the hinge portion 52 as a ratio of the axial thicknessK1 of the cutting portion 53 the cutting element 50 will significantlyreduce risks for i) unintentional folding of the hinge, and ii) reducedpivoting action of the cutting element 50.

Now turning to FIGS. 3-6 a description of the engagement between the cap30 and the neck 20 will be given.

Starting in FIG. 3, the cap 30 is screwed onto the neck 20 for the firsttime, i.e. when the membrane 150 is attached to the neck 20. As can beunderstood by FIG. 3, the cutting elements 50 will bend downwards whenthe cap 30 is unscrewed from the neck 20, whereby the cutting elements50 will be urged inwards and thus cut off the membrane 150 from the neck20.

Preferably, the cutting elements 50 are subject to an idle position inwhich they protrude over a radially outer part of the membrane 150, morespecifically a free end of the cutting elements 50 extend past acircumferential edge of the membrane 150. Hence, the cutting elements 50will retain the membrane 150 within the cap 30 after the cap 30 has beencompletely unscrewed from the neck 20.

Now turning to FIGS. 4-6, a closing sequence of a cap and neck assemblyis shown. Prior to such sequence, it is assumed that the cap 30 has oncebeen unscrewed from the neck 20 such that the membrane 150 has beenseparated from the neck 20.

Starting with FIG. 4, the cap 30 has been screwed on the neck 20. As thecutting elements 50 are retaining the membrane 150 initially, thecutting elements 50 will however be disengaged from the membrane 150when the membrane 150 is reaching the open spout 100 of the neck 20.Hence, as is shown in FIG. 4, the membrane 150 will rest on the spout100 while the cap 30 moves down the neck due to the provision of thethreads, converting a rotational movement to a vertical movement.

In FIG. 4, the membrane 150 is on its upper side in contact with theclosed end of the cap 30, while it rests on the open spout 100 of theneck 20 on its lower side.

When the cap 400 is screwed further downwards, as is shown in FIG. 5,the closed end of the cap 30 will interact with the membrane 150. Hence,the membrane 150 will flex such that its diameter increases, whereby asealing lip 160 of the membrane 150 moves towards the interior side ofthe spout 100.

This procedure is continued as the cap 30 is further rotated down theneck 20. In FIG. 6 the cap 30 is tightly screwed onto the neck 20, andthe membrane 150 has been subjected to an increased flexing. Hence, thesealing lip 160 is urged radially outwards until it contacts theinterior wall of the spout 100 of the neck 20. At the same time, theupper end of the spout 100 engages with a membrane flange 170 such thatthe membrane 150 locks in the desired sealing position. The membrane 150thus seals the spout 100 of the neck 20 such that the outer environmentis unable to affect the food product enclosed within a package equippedwith the neck spout 100, including the membrane 150, and the cap 30.

Now turning to FIG. 7 details of the spout 100 will be described. Asexplained earlier the spout 100 is defined as the upper part of the neck20 through which the package content is discharged. Prior to opening ofthe package the spout 100 thus comprises the membrane 150, however onceopened the membrane 150 is separated from the spout 100. In FIG. 7 thespout 100 is shown prior to opening of the package, i.e. the membrane150 forms part of the spout 100. As indicated by the dashed box in FIG.7, the spout 100 forms the upper part of the neck 20, approximatelystarting from the shoulder 24 and extending upwards.

The spout 100 is formed by a tubular member 110 extending from theshoulder 24 of the neck and upwards. The tubular member 110 has a mainbody 112 and an upper end portion 114 which forms the connection to themembrane 150. During opening, the cutting elements 50 of the cap 30 willcut through the upper end portion 114 of the spout 100 such that themembrane 150 is separated from the main body 112 of the tubular member110.

The membrane 150, forming a circular closure of the spout 100, comprisesa central circular disc member 152 and an outer annular disc member 154.The outer annular disc member is arranged radially in between thecentral circular disc member 152 and a membrane flange 170.

As can be seen in FIG. 7a the outer annular disc member 154 is connectedto the central circular disc member 152 at an angle α, and the membraneflange 170 is connected to the outer annular disc member 154 at an angleβ. These angles facilitates the flexing of the membrane 150 duringre-sealing, such that the entire diameter of the membrane 150 mayincrease as the angles α, β increases due to a downward pressing actionat the centre of the membrane 150. Upon such increase of the membrane's150 diameter, the sealing lip 160 will be urged towards the innersidewalls of the main body 112 of the tubular member 110. In an idleposition where no downward force is applied to the membrane 150 thesealing lip 160 is projecting downwards.

In FIG. 7b the connection between the tubular member 110 and themembrane 150 is shown in further detail. The membrane flange 170 isformed by two adjoining parts; an outer portion 172 which extendsradially outside the end portion 114 of the tubular member 110, and aninner portion 174. The end portion 114 of the tubular member 110 isattached to the interface between the inner and outer portions 172, 174of the membrane flange 170.

The end portion 114 of the tubular member 110 has a certain axial lengthL1. The axial length L1 is e.g. defined as the distance at which theuppermost portion of the tubular member 110 exhibits a substantiallyconstant thickness. Hence, although the main body 112 is tapered towardsthe end portion 114 the axial length L1 does not include such taperedportion. On the other hand, the axial length L1 could also be defined asthe distance at which the uppermost portion of the tubular member 110exhibits a thickness which is less than the thickness of the maintubular member 110 at a position which, when the membrane 150 isseparated from the tubular member 110, forms the outlet of the neck 20.Yet further, the axial length L1 could also be defined as the distanceat which the uppermost portion of the tubular member 110 exhibits athickness which is within a certain percentage, such as e.g. 20-60%, ofthe thickness of the main tubular member 110 at a position which, whenthe membrane 150 is separated from the tubular member 110, forms theoutlet of the neck 20. To give some general values suitable for liquidfood packages, the axial length L1 of the end portion 114 may e.g. be inthe range of 0.1-0.4 mm.

In some embodiments the axial thickness K1 of the cutting portion 53 ofthe cutting element 50 is between 200 and 400% of the axial length L1 ofthe end portion 114.

The axial thickness of the membrane flange 170 varies along its radialextension. As can be seen in FIG. 7b the outer portion 172 has aspecific axial thickness D1 which is equal to, or greater than thethickness D2 of the inner portion 174. Specifically, the axial length L1of the end portion 114 should be in the range of 15-65%, preferably inthe range of 20-50%, of the axial thickness D1 of the outer portion 172of the membrane flange 170. This ratio between the axial length L1 andthe axial thickness D1 has surprisingly proven to allow for a betterre-sealing as a reduced number of plastic projections are formed. Suchplastic projections may otherwise make it more difficult to providere-sealing, especially if they are arranged at right angles.

As mentioned earlier the axial thickness D2 of the inner portion 174 ofthe membrane flange 170 is equal to, or less than the axial thickness D1of the outer portion 172 of the membrane flange 170. As is shown in FIG.7b the outer surface 175 a of the inner portion 174 of the membraneflange 170 coincide with the outer surface 173 a of the outer portion172 of the membrane flange 170. This means that an inner surface 175 bof the inner portion 174 of the membrane flange 170 is arranged at anaxial distance from an inner surface 173 b of the outer portion 172 ofthe membrane flange 170. These inner surfaces 173 b, 175 b may beparallel, and the free height H1 defined as the axial distance betweenthe inner surfaces 173 b, 175 b should always be a positive value, orzero. This means that the inner surface 175 b of the inner portion 174is always at the same level, or above, the inner surface 173 b of theinner portion 172. The configuration of the free height H1 hassurprisingly proven easier penetration of the cutting elements 50, aswell as it reduces the risk for warping or distorting the cuttingelements 50 during penetration.

The sealing lip 160 protrudes downwards into the tubular member 110. Thesealing lip 160 extends from the inner surface 175 b of the innerportion 174, i.e. from an axial position being arranged at a distancefrom the axial end position of the end portion 114 of the tubular member110. The outer radius R1 of the sealing lip 160 is preferably chosen tocorrespond to the outer radius R2 (shown in FIG. 6) of the cuttingelements 50 of the cap 30. Here we measure the outer radii R1 and R2from the line A running through the center of the cap 30 and spout 20 inthe radial direction R towards the outermost surface of the sealing lipand the cutting element 50. This is particularly advantageous because ofthe fact that it allows for a cleaner separation, as well as it allowsthe cutting elements 50 to act as wedges during separation of themembrane 150.

Although the above description has been made with reference to a foodpackages, it should be readily understood that the general principle ofthe neck and cap could be applied to all sorts of packages provided withopening devices.

Further, the invention has mainly been described with reference to a fewembodiments. However, as is readily understood by a person skilled inthe art, other embodiments than the ones disclosed above are equallypossible within the scope of the invention, as defined by the appendedclaims.

All references to “upper”, “lower”, “upwards”, “downwards” etc. are madewith respect to a package standing upright.

1. A cap configured to interact with a neck, said cap comprising: aninner wall portion; and at least one cutting element projecting radiallyinwards from the inner wall portion, said at least one cutting elementhaving a hinge portion connected to the inner wall portion and a cuttingportion extending radially inwards from said hinge portion; wherein afirst axial thickness of the hinge portion is between 35 and 80% of asecond axial thickness of the cutting portion.
 2. The cap according toclaim 1, wherein the first axial thickness of the hinge portion isbetween 3/7 and 5/7 of the second axial thickness of the cuttingportion.
 3. The cap according to claim 1, wherein the first axialthickness of the hinge portion is between 0.3 and 0.5 mm.
 4. The capaccording to claim 1, wherein the at least one cutting elementscomprises between 1 and 7 cutting elements.
 5. The cap according toclaim 1, wherein said at least one cutting elements is configured toseparate a membrane from an associated spout.
 6. An assembly comprisingthe cap according to claim 1, and a spout having a membrane closing atubular member of said spout.
 7. The assembly according to claim 6,wherein said tubular member comprises a main body and an end portionreleasably attached to said membrane, and wherein the second axialthickness of the cutting portion of the at least one cutting element isbetween 200 and 400% of an axial length of said end portion.
 8. Theassembly according to claim 7, wherein said membrane comprises amembrane flange having an outer portion extending radially outside saidend portion of the tubular member.
 9. The assembly according to claim 8,wherein the axial length of the end portion is between 15-65% of anaxial thickness of the outer portion of the membrane flange.
 10. Theassembly according to claim 9, wherein the axial length of the endportion is between 20-50% of the axial thickness of the outer portion ofthe membrane flange.
 11. The assembly according to claim 8, wherein themembrane flange further comprises an inner portion, said end portion ofthe tubular member being attached to an interface between the inner andouter portions of the membrane flange, and wherein an axial thickness ofthe inner portion is equal to or less than the axial thickness of theouter portion.
 12. The assembly according to claim 11, wherein an innersurface of the inner portion of the membrane flange is arranged at anaxial distance from an inner surface of the outer portion of themembrane flange.
 13. The assembly according to claim 12, wherein theinner surface of the inner portion of the membrane flange and the innersurface of the outer portion of the membrane flange are parallel. 14.The assembly according to claim 11, wherein an outer surface of theinner portion of the membrane flange and an outer surface of the outerportion of the membrane flange coincide.
 15. The assembly according toclaim 6, wherein said membrane comprises a sealing lip protruding intosaid tubular member, wherein said sealing lip extends from an axialposition being arranged at a distance (H1) from an axial end position ofthe end portion of the tubular member, and wherein an outer radius ofthe cutting portion of said at least one cutting element corresponds toan outer radius of the sealing lip.